The present disclosure relates generally to rupture disks and, more particularly, to a pressure-compensated rupture disk.
Some existing pressure vessels are pressure-compensated, such as those that actively create pressure. One example is where pressure vessels are used for hydrogen generation using hydride. For such pressure vessels, it may be desirable to relieve pressure at comparatively large volume flow rates in order to prevent pressure vessel overpressure due to blockage or exceedingly high gas generation.
Because certain exothermic reactions, such as with hydrides, increase their rates with temperature, thermal runaway can result in exceedingly high flow rates which would quickly (on the order of seconds) exceed pressure limits due to line backpressure. Additionally, line blockage due to reactants entering the exit line, relief valve failure or other blockages are a real possibility and would result in a similar failure.
It is desirable to prevent catastrophic failure of the pressure vessel, such as through a rupture disk which is sometimes also known as a burst disc, a pressure safety disk, or a burst diaphragm. Overpressure may occur when a hydride reaction exceeds safe flow limits and reactants enters the exit line. The resulting rupture from the rupture disk may save the vessel from damage.
However, using a rupture disk may prove challenging. Ambient factors such as density, corrosion, and fouling may render the rupture disk unpredictable for long term storage. In the case of deep operation, where a snorkel of gas to the surface or where hoses carry the gas over long distances, a rupture disk that lacks pressure compensation would either rupture due to backpressure in the line, or rupture before the relief valve would open due to ambient pressure against that valve. Thus, a pressure-compensated disk is desirable.
There is a need for a rupture disk assembly with three key constraints. First, there is a need for a rupture disk assembly that provides protection of the rupture disk from corrosive environments or fouling. Second, there is a need for a rupture disk assembly that provides a predictable pressure to the back side of the rupture disk. Finally, there is a need for a rupture disk assembly that compensates for depth so that the vessel under normal operating parameters would not cause the disk to burst prematurely.